CN114593645A

CN114593645A - Active and passive multi-stage buffering energy-absorbing structure for survival requirement of components in projectile body

Info

Publication number: CN114593645A
Application number: CN202210228590.8A
Authority: CN
Inventors: 张青松; 贾山; 陈金宝; 蔡成志; 高翔宇
Original assignee: Nanjing University of Aeronautics and Astronautics
Current assignee: Nanjing University of Aeronautics and Astronautics
Priority date: 2022-03-10
Filing date: 2022-03-10
Publication date: 2022-06-07
Anticipated expiration: 2042-03-10
Also published as: CN114593645B

Abstract

The invention discloses an active and passive multistage buffering energy-absorbing structure for survival requirements of components in a projectile body. The first passive energy absorption structure comprises a pull rod and an expansion pipe sleeved outside the pull rod; the second passive energy absorption structure comprises a first energy absorption ring connected with the tray in a welding mode and a second energy absorption ring detachably mounted on the secondary missile; the active energy absorption structure comprises a cylinder body, a piston, a rod body and a magnetic coil. Compared with the prior art, the active and passive multistage buffering energy absorption structure can perform buffering energy absorption at the moment when the positioning missile hits the target, and can ensure the survival rate of the core assembly of the positioning missile so as to return the relevant information of the hit target.

Description

Active and passive multi-stage buffering energy-absorbing structure for survival requirement of components in projectile body

Technical Field

The invention relates to the technical field of buffering and energy absorption, in particular to an active and passive multistage buffering and energy absorption structure for survival requirements of components in a projectile body.

Background

With the continuous development of war form towards digitalization, unmanned, remote and intelligent, the strike accuracy is undoubtedly an important index for future war. In the missile hitting process, due to the influences of factors such as the weather environment and calibration errors, the actual drop point and the expected drop point often have certain deviation. In addition, if the enemy interferes with the functions of target positioning, navigation guidance and the like of the satellite of the enemy, the missile hitting accuracy is further reduced. Under the strong interference environment, if the position coordinates and the motion state of a target to be struck are recalibrated by using a positioning missile which can transmit information such as damage effect and a drop point position back, the trajectory correction of the subsequent missile is realized, the striking effect can be obviously improved, and the method has important significance for acquiring initiative in future war in China.

The research results of China and main countries in the western world on the buffering energy-absorbing device are widely applied to the fields of aerospace, special equipment and the like, the technical maturity is very high, but the impact load in related application scenes is of a conventional magnitude, and the overload magnitude of the missile in the moment of contact with the ground is far greater than that of the missile. When the missile is positioned to impact a target at a high speed, a built-in core component for returning information such as position coordinates and instantaneous overload bears great mechanical impact. Therefore, how to realize efficient energy dissipation and ensure the survival rate of the core components of the positioning missiles is a technical problem to be solved urgently by those skilled in the art.

Disclosure of Invention

The invention aims to provide an active and passive multistage buffering energy-absorbing structure for meeting the survival requirement of components in a projectile body, which can perform buffering energy absorption at the moment when a positioned missile strikes a target, so that the survival rate of the core component of the positioned missile is ensured, and relevant information of the struck target is returned.

In order to achieve the purpose, the invention provides the following scheme:

the invention discloses an active and passive multilevel buffering energy-absorbing structure facing to the survival requirement of an internal assembly of a missile body, which is used for being arranged between the bottom of a first-level missile and the bottom of a second-level missile of a positioning missile and comprises the following components:

the tray is used for connecting the communication component of the positioning missile;

the first passive energy absorption structure comprises a pull rod and an expansion pipe sleeved outside the pull rod; the pull rod penetrates through the tray along the axial direction of the tray, the first end of the pull rod is used for being connected with the bottom of the first-stage missile, and the second end of the pull rod is provided with a conical section with the pointed end facing the tray; the tray and the conical section are respectively positioned on two sides of the expansion pipe and used for extruding the expansion pipe along the axial direction;

the active energy absorption structure comprises a cylinder body, a piston, a rod body and a magnetic coil; the cylinder body is used for containing magnetorheological fluid and is connected with the bottom of the secondary missile; the first end of the rod body is connected with the tray, and the second end of the rod body is connected with the piston; the piston is arranged in the cylinder body in a sliding mode, and a magnetic current through hole for the magnetorheological fluid to pass through is formed in the piston; the magnetic coil is wound and arranged outside the cylinder body;

a second passive energy absorbing structure comprising a first energy absorbing ring and a second energy absorbing ring; the first energy-absorbing ring is arranged on the tray, and the second energy-absorbing ring is used for being arranged on the secondary missile; the first energy absorption ring is provided with first energy absorption teeth, the second energy absorption ring is provided with second energy absorption teeth, the first energy absorption teeth and the second energy absorption teeth are arranged adjacently, and the tooth tips of the first energy absorption teeth and the tooth tips of the second energy absorption teeth are staggered; when the first energy absorbing ring and the second energy absorbing ring are close to each other, the first energy absorbing teeth and the second energy absorbing teeth are extruded to deform mutually.

Preferably, the first energy-absorbing ring is connected with the tray in a welding mode, and the second energy-absorbing ring is a hoop and is detachably mounted on the secondary missile; a limiting clamping groove used for being in limiting contact with the secondary missile is arranged on the inner side of the second energy absorption ring, the limiting clamping groove comprises an annular end surface and a cylindrical surface, and the end surface is connected with the cylindrical surface; the end face is used for limiting and abutting against the bottom end face of the second-stage guided missile, and the cylindrical surface is used for being sleeved on the outer side of the bottom side face of the second-stage guided missile.

Preferably, a plurality of the first passive energy-absorbing structures form a group of the passive energy-absorbing structures, and the plurality of groups of the passive energy-absorbing structures are uniformly distributed along the circumferential direction by taking the axial direction of the tray as the center.

Preferably, a set of said first passive energy absorbing structures is arranged in a row and equally spaced.

Preferably, the tray includes cylinder and first shirt rim, the cylinder is kept away from the one end of initiative energy-absorbing structure is equipped with the holding chamber, the holding chamber is used for holding the communication subassembly of location guided missile, first shirt rim is fixed in on the lateral surface of cylinder and with the cylinder is coaxial, the pull rod passes first shirt rim.

Preferably, the first end of the pull rod is used for being in threaded connection with the first-stage missile, the first end of the expansion pipe is connected with the tray in a welded mode, and the second end of the expansion pipe abuts against the conical surface of the conical section.

Preferably, the cylinder body comprises a bottom cover and a top cover, the bottom cover is detachably connected with the top cover through a fastener, so that an inner cavity for containing magnetorheological fluid is formed between the bottom cover and the top cover, and a first sealing ring is arranged between the bottom cover and the top cover; the top cover is provided with a sealing through hole for the rod body to pass through, and a second sealing ring is arranged between the rod body and the sealing through hole.

Preferably, a wire slot is arranged on the outer side surface of the cylinder body, and the magnetic coil is wound in the wire slot.

Preferably, the first end of the rod body is in threaded connection with the tray, and the second end of the rod body is in threaded connection with the piston.

Compared with the prior art, the invention has the following technical effects:

the buffering energy-absorbing structure has the characteristics of adjustable parameters, wide buffering energy-absorbing range, short buffering action formation, small space occupation ratio, strong active and passive buffering energy-absorbing effects and the like, and the magnetorheological fluid active buffering energy-absorbing device can adjust the magnetic flux of the magnetic coil in advance according to the self flight of a projectile body while the passive structure buffers and absorbs energy, so as to adjust the damping characteristic of the built-in magnetorheological fluid in real time.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a schematic diagram of a position relationship between an active and passive multi-stage buffering energy-absorbing structure and a first-stage missile and a second-stage missile according to the survival requirement of an internal assembly of a missile body in the embodiment;

FIG. 2 is a schematic overall view of an active and passive multi-stage buffering and energy absorbing structure for meeting the survival requirement of the internal components of the projectile body according to the embodiment;

FIG. 3 is a schematic view from a perspective of the position relationship of the tray and the first passive energy absorbing structure;

FIG. 4 is a schematic view of a tray from one perspective;

FIG. 5 is a schematic view of another perspective of the tray;

FIG. 6 is a schematic view from another perspective of the positional relationship of the tray and the first passive energy absorbing structure;

FIG. 7 is a schematic view of a piston;

FIG. 8 is a schematic view of the position relationship between the rod and the piston;

FIG. 9 is a schematic view of a top cover from one perspective;

FIG. 10 is a schematic view of the top cover from another perspective;

FIG. 11 is a schematic view of a bottom cover;

FIG. 12 is a schematic view of a positional relationship between a tray and an active energy absorbing structure;

FIG. 13 is a schematic view of an active energy absorbing structure;

FIG. 14 is a schematic view of a magnetic coil;

FIG. 15 is a schematic view of a second passive energy absorbing structure;

FIG. 16 is a schematic view of a second energy absorbing ring.

Description of reference numerals: 1-first-class missile; 2-second-level missiles; 3-an active and passive multi-stage buffering energy-absorbing structure facing the survival requirement of components in the projectile body; 401-a first tie rod; 402-a second tie rod; 403-a third pull rod; 404-a fourth pull rod; 408-a first expansion tube; 407-second expansion pipe; 406-a third expansion tube; 405-a fourth expansion tube; 5-a tray; 501-a first pull rod through hole; 502-second tie rod through hole; 503-third tie rod through hole; 504-fourth tie rod through hole; 505-a first rod threaded hole; 506-a containing cavity; 6-a first energy absorbing ring; 601-first energy absorbing teeth; 7-a second energy-absorbing ring; 701-fastening plates; 702-a limiting card slot; 703-a second gullet; 8-a piston; 801-magnetic flow through holes; 802-second rod threaded hole; 9-a rod body; 10-a top cover; 1001-sealing the through hole; 1002-a third seal groove; 1003-countersunk through holes; 1004 — a second seal groove; 11-a bottom cover; 1101-lumen; 1102-a first seal groove; 1104-a first threaded hole; 1105-a wire slot; 1106-a second skirt; 1107-second threaded hole; 12-a magnetic coil; 13-communication component.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below. Except for special description, the connection of the two structures in this embodiment may be direct fixed connection, that is, the two structures are in direct contact, or indirect fixed connection, that is, an intermediate structure is disposed between the two structures, as long as the two structures are fixed relatively. In this embodiment, the bottom of the first-stage missile 1 and the bottom of the second-stage missile 2 are both ends far away from the warhead, and the second-stage missile 2 is arranged inside the first-stage missile 1 according to common knowledge.

Referring to fig. 1 to 16, the embodiment provides an active and passive multistage buffering energy-absorbing structure 3 facing to the survival requirement of an internal component of a missile body, which is used for being installed between the bottom of a first-stage missile 1 and the bottom of a second-stage missile 2 of a positioning missile and comprises a tray 5, a first passive energy-absorbing structure, an active energy-absorbing structure and a second passive energy-absorbing structure.

The tray 5 is used for being connected with the communication assembly 13 of the positioning missile, and the communication assembly 13 in the positioning missile can be buffered by buffering the tray 5.

The first passive energy absorption structure comprises a pull rod and an expansion pipe sleeved on the outer side of the pull rod, the pull rod is used for absorbing energy through stretching deformation, the expansion pipe is used for absorbing energy through expansion deformation, and the pull rod and the expansion pipe are preferably made of metal materials. The pull rod passes through the tray 5 along the axial direction of the tray 5, and a pull rod through hole for the pull rod to pass through is arranged on the tray 5. The first end of the pull rod is used for connecting with the bottom of the primary missile 1, preferably in a threaded connection, and the second end of the pull rod is provided with a conical section with the tip facing the tray 5. The tray 5 and the conical section are respectively positioned at two sides of the expanding tube and used for extruding the expanding tube along the axial direction.

The active energy absorption structure comprises a cylinder body, a piston 8, a rod body 9 and a magnetic coil 12. The cylinder body is used for containing magnetorheological fluid and is connected with the bottom of the second-level missile 2. The first end of the rod body 9 is connected with the tray 5, and the second end of the rod body 9 is connected with the piston 8. The piston 8 is arranged in the cylinder body in a sliding mode, and a magnetic current through hole 801 for the magnetorheological fluid to pass through is formed in the piston 8. The magnetic coil 12 is wound and arranged outside the cylinder. By adjusting the magnitude of the magnetic flux generated by the magnetic coil 12, the viscosity coefficient of the magnetorheological fluid can be adjusted, and the real-time adjustment of the absorption efficiency is realized aiming at impact loads of different magnitudes.

The second passive energy absorbing structure comprises a first energy absorbing ring 6 and a second energy absorbing ring 7. The first energy absorbing ring 6 is arranged on the tray 5, and the second energy absorbing ring 7 is used for being arranged on the second-level missile 2. The first energy absorbing ring 6 is provided with first energy absorbing teeth 601, and a first tooth groove is formed between every two adjacent first energy absorbing teeth 601. The second energy-absorbing ring 7 is provided with second energy-absorbing teeth, and a second tooth groove 703 is formed between every two adjacent second energy-absorbing teeth. The first energy-absorbing teeth 601 are arranged adjacent to the second energy-absorbing teeth, and the tooth tips of the first energy-absorbing teeth 601 are staggered with the tooth tips of the second energy-absorbing teeth. When the first energy-absorbing ring 6 and the second energy-absorbing ring 7 approach each other, the first energy-absorbing teeth 601 and the second energy-absorbing teeth are extruded to deform each other.

The working principle of the active and passive multistage buffering energy-absorbing structure 3 facing the survival requirement of the internal components of the projectile body is as follows:

the buffering and energy absorbing process of the structure is mainly divided into two stages so as to reduce the kinetic energy of the tray 5 and the communication assembly 13 on the tray 5.

In a first phase, the first passive energy absorbing structure absorbs energy: when the first-stage missile 1 is in contact with a target surface, the second-stage missile 2 continues to move along the original direction relative to the first-stage missile 1 under the inertia effect. At the moment, the pull rod is under the action of tensile force and generates tensile deformation so as to absorb energy. Meanwhile, the conical section on the pull rod and the tray 5 respectively extrude the expansion pipe from two sides, so that the expansion pipe is expanded and deformed to absorb energy.

In the second stage, the second passive energy absorption structure and the active energy absorption structure absorb energy together: after the pull rod of the first passive energy absorption structure is pulled off, the second-level guided missile 2 moves forwards relative to the first-level guided missile 1. At this time, on the one hand, the rod body 9 drives the piston 8 to move towards the direction far away from the second-level missile 2, and the magnetorheological fluid inside the cylinder body flows through the magnetorheological hole 801 on the piston 8, so that energy is absorbed through damping between the magnetorheological fluid and the piston 8. On the other hand, the first energy-absorbing tooth 601 and the second energy-absorbing tooth contact each other and are crushed to absorb energy.

In the process, the energy absorption mode of the pull rod, the expansion pipe and the energy absorption teeth is passive energy absorption. The damping coefficient of the magnetorheological fluid can be adjusted through the magnetic flux generated by the magnetic coil 12, and the magnetorheological fluid is active energy absorption. Therefore, the buffering and energy absorbing structure can realize active and passive multi-stage buffering and energy absorbing.

In this embodiment, the distance between two adjacent second energy-absorbing teeth is twice the distance between two adjacent first energy-absorbing teeth 601, and the tooth tips of the second energy-absorbing teeth are aligned with the tooth grooves of the first energy-absorbing teeth 601. Other arrangements can be selected by those skilled in the art according to different actual needs.

It should be noted that, according to different combat mission processes, the overload peak value of the communication component 13 on the pallet 5 can be estimated, and the passive buffering function with different overload buffering and energy absorbing characteristics can be realized by adjusting the characteristic parameters (such as axial and radial dimensions) of the pull rod, the material parameters of the tube expansion device and other technical means. Meanwhile, the magnitude of the magnetic flux generated by the magnetic coil 12 can be controlled by a control system arranged in the bomb body, the viscosity coefficient of the magnetorheological fluid is adjusted, and further the active buffering function with different overload buffering and energy absorbing characteristics is realized. In addition, the passive buffering function with different overload buffering and energy absorbing characteristics is realized by adjusting the size parameters of the first energy-absorbing tooth 601 and the second energy-absorbing tooth. Through the combination of the active and passive buffer devices, the buffer protection function of the communication assembly 13 under all working conditions is realized, and information such as position coordinates, instantaneous overload and the like is transmitted back in time.

In this embodiment, the first energy-absorbing ring 6 is welded to the tray 5, the second energy-absorbing ring 7 is a hoop, a fastening plate 701 is disposed at an opening end of the hoop, and a fastening through hole is disposed on the fastening plate 701 and used for installing a fastening member (e.g., a bolt or a nut assembly). The fastening plates 701 at the two adjacent open ends of the hoop are tightly attached through locking of the fasteners, so that the hoop is detachably mounted on the secondary missile 2. The inner side of the second energy absorption ring 7 is provided with a limiting clamping groove 702 used for being in limiting contact with the second-level missile 2, the limiting clamping groove 702 comprises a circular end face and a cylindrical surface, and the end face is connected with the cylindrical surface. The end face is used for limiting and abutting against the bottom end face of the second-stage guided missile 2, and the cylindrical surface is sleeved on the outer side of the bottom side face of the second-stage guided missile 2. Other connecting modes of the first energy-absorbing ring 6 and the second energy-absorbing ring 7 can be selected by a person skilled in the art according to different actual needs.

In order to absorb energy more uniformly, in this embodiment, the plurality of first passive energy-absorbing structures form a group of passive energy-absorbing structures, the plurality of groups of passive energy-absorbing structures are uniformly distributed along the circumferential direction with the axial direction of the tray 5 as the center, and the group of first passive energy-absorbing structures are arranged in a row and are distributed at equal intervals. The passive energy absorbing structures are preferably divided into four groups, each group preferably comprising seven passive energy absorbing structures. In the seven passive energy absorption structures, from the middle to two sides, the pull rods comprise a first pull rod 401, a second pull rod 402, a third pull rod 403 and a fourth pull rod 404, wherein the length and the radius of the first pull rod 401 are gradually reduced, and the diameter of the first pull rod through hole is gradually reduced from the middle to two sides, and the pull rod through holes comprise a first pull rod through hole 501, a second pull rod through hole 502, a third pull rod through hole 503 and a fourth pull rod through hole 504. The expansion tubes include a first expansion tube 408, a second expansion tube 407, a third expansion tube 406, and a fourth expansion tube 405 of progressively decreasing length and outer diameter. The arrangement mode enables the energy absorption function of the passive energy absorption structure positioned in the middle to be strongest. In the energy absorption process, for a group of passive energy absorption structures, a plurality of passive energy absorption structures fail one by one from outside to inside without failure at the same time, so that the smoothness of the energy absorption process is ensured.

In this embodiment, the tray 5 includes a cylinder and a first skirt. And one end of the column body, which is far away from the active energy absorption structure, is provided with a containing cavity 506, and the containing cavity 506 is used for containing the communication assembly 13 for positioning the missile. The first skirt edge is fixed on the outer side surface of the cylinder body and is coaxial with the cylinder body, and the pull rod penetrates through the first skirt edge. Other shapes of tray 5 may be selected by those skilled in the art according to actual needs.

In this embodiment, the first end of the pull rod is provided with an external thread for being in threaded connection with the first-level missile 1, the first end of the expansion pipe is welded with the tray 5, and the second end of the expansion pipe is abutted to the tapered surface of the tapered section. Other fixing manners of the first end of the pull rod and the first end of the expansion tube can be selected by those skilled in the art according to different actual needs, for example, the fixing is performed through screws.

In this embodiment, the first end of the rod 9 is connected to the tray 5 by a screw, the tray 5 is provided with a first rod screw hole 505 for installing the first end of the rod 9, the second end of the rod 9 is connected to the piston 8 by a screw, and the piston 8 is provided with a second rod screw hole 802 for installing the second end of the rod 9. Other fixing means of the rod body 9, such as welding, can be selected by those skilled in the art according to the actual needs.

In this embodiment, the cylinder body includes a bottom cover 11 and a top cover 10, the bottom cover 11 is detachably connected to the top cover 10 through a fastener, the top cover 10 is provided with a countersunk through hole 1003 for mounting the fastener, and the bottom cover 11 is provided with a first threaded hole 1104 for mounting the fastener. An inner cavity 1101 for containing magnetorheological fluid is formed between the bottom cover 11 and the top cover 10, and a first sealing ring is arranged between the bottom cover 11 and the top cover 10 and comprises two first sealing rings. The bottom cover 11 is provided with two first seal grooves 1102 for mounting first seal rings, the number of the first seal grooves 1102 is two, the top cover 10 is provided with two second seal grooves 1004 for mounting the first seal rings, and the number of the second seal grooves 1004 is two. A sealing through hole 1001 for the rod body 9 to pass through is formed in the top cover 10, a second sealing ring is arranged between the rod body 9 and the sealing through hole 1001, and a third sealing groove 1002 for mounting the second sealing ring is formed in the sealing through hole 1001. And a second skirt edge 1106 is arranged at one end of the bottom cover 11 far away from the top cover 10, the second skirt edge 1106 is detachably connected with the second-stage missile 2 through a fastener, and a second threaded hole 1107 for installing the fastener is formed in the second skirt edge 1106. According to different actual needs, a person skilled in the art can select other forms of cylinder body as long as the cylinder body can contain magnetorheological fluid and provide damping when the piston 8 moves relative to the cylinder body. The number of the first sealing rings and the second sealing rings can be selected as required, and sealing can be achieved.

In order to facilitate winding the magnetic coil 12 and prevent the magnetic coil 12 from displacing, in this embodiment, a wire slot 1105 is disposed on the outer side surface of the cylinder body, and the magnetic coil 12 is wound in the wire slot 1105.

The principle and the implementation mode of the present invention are explained by applying specific examples in the present specification, and the above descriptions of the examples are only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.

Claims

1. The utility model provides an active passive multistage buffering energy-absorbing structure towards demand of living of internal subassembly of projectile for install between the one-level guided missile bottom and second grade guided missile bottom of location guided missile, its characterized in that includes:

the tray is used for connecting the communication assembly of the positioning missile;

2. The active and passive multistage buffering energy absorption structure facing the survival requirement of an internal assembly of the projectile body as claimed in claim 1, wherein the first energy absorption ring is connected with the tray in a welding manner, and the second energy absorption ring is a hoop and is detachably mounted on the secondary missile; a limiting clamping groove used for being in limiting contact with the secondary missile is arranged on the inner side of the second energy absorption ring, the limiting clamping groove comprises an annular end surface and a cylindrical surface, and the end surface is connected with the cylindrical surface; the end face is used for limiting and abutting against the bottom end face of the second-stage guided missile, and the cylindrical surface is used for being sleeved on the outer side of the bottom side face of the second-stage guided missile.

3. The active and passive multistage buffering energy-absorbing structure for survival requirements of components in a projectile body as claimed in claim 1, wherein a plurality of first passive energy-absorbing structures form a group of passive energy-absorbing structures, and the plurality of groups of passive energy-absorbing structures are uniformly distributed in a circumferential direction with an axial direction of the tray as a center.

4. The active and passive multi-stage energy-absorbing buffering structure facing to the survival requirement of an internal assembly of an elastomer as claimed in claim 3, wherein a group of the first passive energy-absorbing structures are arranged in a row and are distributed at equal intervals.

5. The active and passive multistage buffering and energy absorbing structure for survival demand of internal components of a projectile body as claimed in claim 1, wherein the tray comprises a cylinder and a first skirt edge, one end of the cylinder far away from the active energy absorbing structure is provided with a containing cavity for containing the communication component of the positioning missile, the first skirt edge is fixed on the outer side surface of the cylinder and is coaxial with the cylinder, and the pull rod penetrates through the first skirt edge.

6. The active and passive multistage buffering and energy absorbing structure for survival requirements of internal components of projectiles as claimed in claim 1, wherein a first end of the pull rod is used for being in threaded connection with the first-stage missile, a first end of the expansion tube is connected with the tray in a welding manner, and a second end of the expansion tube abuts against the tapered surface of the tapered section.

7. The active-passive multistage buffering energy-absorbing structure facing to the survival demand of an internal component of the projectile body as recited in claim 1, wherein the cylinder body comprises a bottom cover and a top cover, the bottom cover and the top cover are detachably connected through a fastener, so that an inner cavity for containing magnetorheological fluid is formed between the bottom cover and the top cover, and a first sealing ring is arranged between the bottom cover and the top cover; the top cover is provided with a sealing through hole for the rod body to pass through, and a second sealing ring is arranged between the rod body and the sealing through hole.

8. The active and passive multistage buffering and energy absorbing structure for survival demand of internal components of bullet bodies according to claim 1, wherein the outer side surface of the cylinder body is provided with wire grooves, and the magnetic coils are wound and arranged in the wire grooves.

9. The active and passive multi-stage buffering and energy absorbing structure for survival of internal components of a projectile according to claim 1, wherein a first end of said rod body is threadedly connected to said tray and a second end of said rod body is threadedly connected to said piston.